1. Field of the Invention
The present invention relates to a wiper system for a vehicle.
2. Description of Related Art
For example, Japanese Unexamined Utility Model Publication No. H07-5999 and Japanese Unexamined Patent Publication No. 2005-82027 disclose wiper systems for a vehicle. Specifically, the wiper system of Japanese Unexamined Utility Model Publication No. H07-5999 is an opposed wiper system, which has two wiper arms reciprocally pivoted in opposite directions, respectively. In this wiper system, a crank arm is connected to an output shaft of a wiper motor, and an intermediate link is connected to the crank arm through a connecting rod. A longitudinal center of the intermediate link is pivotably supported, and two drive rods are connected to end portions, respectively, of the intermediate link. A corresponding drive lever, to which a corresponding wiper arm is fixed, is connected to each drive rod.
When the output shaft of the motor is continuously rotated in the single direction, the rotational force of the motor is conducted to the intermediate link through the crank arm and the connecting rod, so that the intermediate link is reciprocally pivoted. Through the reciprocal pivotal movement of the intermediate link, the drive rods are reciprocated to reciprocally pivot the drive levers and the wiper arms.
In the case of the wiper system recited in Japanese Unexamined Patent Publication No. 2005-82027, a crank arm is connected to an output shaft of a wiper motor, and a pivot lever is connected to the crank arm through a link. A pivot shaft, to which one wiper arm is fixed, is provided to the pivot lever. A four-bar linkage is connected to the pivot lever through a link, and the other wiper arm is fixed to this four-bar linkage.
When the output shaft of the wiper motor is continuously rotated in the single direction, the rotational force of the wiper motor is conducted to the pivot lever and the four-bar linkage through the crank arm and the link to reciprocally pivot the pivot lever and each link of the four-bar linkage to reciprocally pivot the wiper arms.
In the case of the opposed wiper system recited in Japanese Unexamined Utility Model Publication No. H07-5999, the intermediate link is required to pivot the wiper arms in opposite directions, respectively. Furthermore, in order to reciprocally pivot the intermediate link, the crank arm and the connecting rod need to be provided between the motor and the intermediate link. Thus, in order to reduce the number of components and to reduce the costs, further improvements are required.
Furthermore, in the case of the wiper system recited in Japanese Unexamined Patent Publication No. 2005-82027, the four-bar linkage is provided to the one of the two wiper arms. Thus, in order to coincide the wiping directions of the two wiper arms with each other, the main lever, which forms the four-bar linkage at the one wiper arm, needs to be pivoted in the direction opposite from that of the pivot lever of the other wiper arm. Also, the main lever and the sub-lever, which form the four-bar linkage, need to be placed on the side opposite from the pivot lever of the other wiper arm in the transverse direction of the system (in a front-to-rear direction of the vehicle). That is, the main lever and the sub-lever of the four-bar linkage are placed at the rear side in the front-to-rear direction of the vehicle, and the pivot lever at the other wiper arm is placed at the front side in the front-to-rear direction of the vehicle. However, in such a case, the size of the entire system having the pivot lever and the four-bar linkage is disadvantageously increased. Thus, in order to reduce the size of the entire system in the transverse direction of the system, further improvements are required.